Safety device for punch presses and the like



A ril 8 1924,. v 1,4893% F. CREBITY SAFETY DEVICE FOR PUNCH PRESSES AND THE LIKE Filed May 29 1920 5 Sheets-Sheet 1 April 8 1924. 1,489,309

F. CREDITY SAFETY DEVICE FOR PUNCH PRESSES AND THE'LIKE Filed y 29 0 5 Sheets-Sheet 3 F. CREDITY April 8 1924' iwm April 8 1924.

F. CREDITY SAFETY DEVICE FOR PUNCH PRESSES AND THE LIKE Fil y 29 1920 5 Sheets-Sheet 5 Patented Apr. 8, 1924.

UNITED STATES PATENT OFFICE.

OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

SAFETY DEVICE FOR PUNCH PRESSES AND THE LIKE.

Application filed May 29, 1920. Serial No. 385,146.

To all whom it may concern.

Be it known that I, FRED CREDITY, a citizen of the United States, residing in Maywood, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Safety Devices for Punch Presses and the like, of which the following is a specification. v

This invention. relates in general to feeding mechanism for punch presses and the like, and has more particular refeience to feeding mechanism, wherein a strip of sheet metal is fed into a punch press to have'a number of articles formed therefrom, by 5 successive action of the die parts.

It will, however, be manifest, that with slight changes, the invention may be used for feeding sheet metal to other forms of punch presses and to other types of m..-

chines.

My present invention, however, while usable in connection with other and different apparatus, has more particular reference, particularly as embodied for the purposes of illustration in this specification, to'the apparatus shown, described and claimed in application for patent Serial No. 385,203, filed May 29, 1920, by Hugo Schoendelen, for improvements in safety devices for punch presses and the like.

A principal object of the present invention is the provision of mechanism and devices for feeding the, metal into operative relation with a press or other apparatus automatically, and so constructed and arranged, that after two sheets or strips of material have been forced into the feeding mechanism, the action will cease without damaging any following sheets by attempting to force them into parts of the apparatus clogged or otherwise out of condition to receive them.

Another important object of my invention is the provision of a control for feeding inoperative or out of effect, when devices of the character described in the Schoendelen application, and provided to protect against certain adverseconditions, are enaged inthe actual stopping of'the main eed mechanism.

Numerous objects and advantages of the invention will be apparent fromthe followmeans, which\will render said feeding means ing description, which taken in connection with the accompanying drawings, discloses a referred embodiment thereof.

eferring to the drawings Fig. 1 is an end elevation of a press equipped in accordance with my present invention;

Fig. 2 is a front elevation thereof;

Fig. 3 is an enlarged fragmentary detailof a portion of the apparatus;

Fig. 4 is an enlarged perspective View;

Fig. 5 is a transverse section through a part of the feeding mechanism; and

Fig. 6 is a partial plan, view, parts being shown in section of the same.

The apparatus shown on the drawings and selected for the purposes of illustration, is a punch press adapted to form articles such as can ends, from strip material. The strips are automatically fed into a position, from which they may be advanced to the dies, by progressive steps, each step occurring after a die action and being wholly automatic in action. A number of can ends or covers are ,formed from each stripand the apparatus is so constructed and arranged, that after every descent of the die, a strip is advanced an appropriate distance, to present the part of the strip from which the next article is to be formed. The apparatus also provides for the feeding of the strips in such manner as to. cause them to' be taken singly from the stack and to follow each other closely past the dies, so that the dies may reciprocate continuously and without interruption.

In this action, the strips are picked up from the stack by suction heads, which arrange them opposite a slot into which they are thrust sidewise by pusher blocks. Ar-

riving in the slot, each sheet isfed forward with a step-by-step movement between the dies. Means are provided in the apparatus for preventing the feeding to the die, should more than a single blank be positioned in the slot and to stop the feeding action under other adverse conditions.

The apparatus comprises a support 11, carrying a press bed or frame 12, in which are mounted the operative parts. .The bed extends up at one side to provide the two standards 13, providingthe guides 14,'for

the upper reciprocatingdie head 15. At the top, these standards are provided with bearings 16, for the shaft 17, which is the main power shaft and which carries the pulley 18 to actuate the apparatus. The shaft 17 is a crank shaft and the die head 15 is moved up and down between the guides by the crank action in the usual manner. A stack holder 19 is positioned on the bed and at a side thereof and is adapted to contain a stack of blanks or strips to be operated upon, such blanks or strips being indicated at 21. These blanks are lifted or moved singly from the stack by three suction heads 22, mounted upon the end of reciprocating rods or pipes 23, axially movable through bearings,

extending up from the bed. The pipes 23 are. connected by pipes 24 and couplings 25 to form a unitary structure and the pipes 23 and 24 and the couplings 25 are hollow and in communication through a valve struc ture 26. with a vacuum or exhaust pipe 28. The valve 26 is controlled by a slide rod 29, positioned on the right hand suction head and operable by a sheet, when the head contacts therewith, to open the exhaust valve by upward movement of a rod 31'. The suction mechanism just described, is caused t'o reciprocate by a link 32, having a slot 33 in its upper end engaged by a pin. 34, upon a lever 35, pivoted at 36, from the bed and connected'by a link 37, with a crank disk 38 fixed upon a stub shaft 39. This shaft also carries a gear 41, meshing with a pinion 42, upon a stub shaft 43 and driven by a gear 44, meshing with a pinion 45, upon shaft 17 Thegearing is so constructed, that the suction heads move down to pick up a sheet or strip 21, for each number of die reciprocations needed in the formation of the-number of articles formed from the strip.

The suction heads carry the strips into registration with a feed slot, into which the strips are pushed sidewise by reciprocating pusher blocks 46. These pusher blocks are mounted upon rods 47, having bearings at 48, extending up from the bed. Reciprocation is imparted to the push rods from a shaft 49 through arms or links 51. The shaft 49 is mounted in bearings 52,,and is connected by an arm 53 and the link 54, with. a bell crank lever 55 pivoted on the stub. shaft 36. This lever carries a roller 56 and gauging the cam 57 on the shaft 39, the roller being held against the cam by a spring 53, which spring actuates the pusher blocks in the operative stroke.

This action of the pusher bars tends to move-the strips into the slot which isindieated at 71, and is perhaps best seen in Fig. 5. The sheets after being positioned in theslot are fed ahead along the slot in a step-by-step movement, by a finger slide bar 72. This finger slide bar is actuated by a link 73 from an angle plate 74, forming abell crank lever and piyfrom the suction heads and oted at 75 in the frame, and connected by a connecting link 76, with a crank disk 77, arranged upon the left hand end of shaft 17.

Means are provided for causing an interruption to the feeding movement of the finger bar, if and when two sheets are forced into the slot 71. This means comprises a. spring held pin 78, normally extending across the slot 71 and adapted to be pushed back by the sheet moving down into the slot. If a single sheet be inserted, the pin 78 is pushed back without effect upon the remainder of the apparatus, but if two sheets be inserted, the corresponding movement of the pin 78 causes further feeding by the finger bar to cease; A latch or lever 79, having a hook end 81, is'pivoted at 82 on the left hand bearing 52. One end of this lever extends over the'pin 78 and is provided with a set'screw 83, forming an adjustable stop and gaugeable by the pin when the pin is lifted by the insertion of two sheets. A

spring 84 normally holds the'lever 79 in engagement with an upstanding arm 85 of athree armed lever pivoted at 86. This lever is normally pulled away from theposition shown in full lines in Fig. 6, which is the position occupied by itwhen the feeding mechanism is operated by a spring 87. second arm 88 of this lever is connected by a link 89 with a lever 91, pivoted at 92 on the end of the stack holder. Said lever 91, when the parts are arranged in normal position, is disposed alongside the travel of a head 93, on the end of the finger bar, and when the lever 79 is moved forward (as seen in Fig. 6) as the result of the insertion of two sheets in the'slot, thereby releasing the hook 31 from the three arm lever and causing the lever 91 to move from the'position shown in full lines in Fig. 6, to that shown indotted lines, the lever 91 is disposed in the path of travel of the head 93. This prevents movement of the finger bar and results in disconnection of the link 73 from the bell crank plate 74. The link 73 has a readily detachable connection 95 with the plate 74 as may be seen in dotted lines in Fig. 2.

In order that this disconnection may not result in further increasing the number of sheets in the slot and to prevent damage to subsequent sheets picked up by the suction heads, I provide means for rendering the suction devices inoperative and also for preventing action of the pusher blocks. As has already been stated, there is communication between the suction heads and the breaking of the suction at any one head destroys at the others as well. A lever 96 is pivoted at 97 in the bed and has one arm 98 provided with a set screw 99. disposed above and adiacent, the third arm 101 of the three arm lever. This lever has its other arm formed side the left hand suction head, as may be seen in Fig. 3. Normally this rod is adapted to be lifted or pushed back bythe sheet, as the suction head brings the sheet into registration with the slot. When, however, the three armed lever is released, its end 102 prevents this pushing back of the rod 103, with the result that the suction is broken at this suction head, and as a result at the other suction heads also, permitting the sheet to drop back upon the stack.

The reciprocating pusher rod 47 is provided with a stop 105 and an arm 106, pivoted at 107 normally rests behind this stop and prevents the spring 58 pulling back the pushers, unless the arm 106 be lifted. This arm islifted during the normal operation of the apparatus by a collar 108 on the rod 103, when this rod is pushed back by the blank. When, however, the rod 103 is prevented from moving the arm 106 is not lifted and operative movement of the pushers is prevented.

It Will be manifest that feeding of any blank into the chute is instantly prevented if the conditions in the chute have caused the pin 78 to be moved out beyond this normal distance, and further crowding of the chute or damage or bending of the strips is positively prevented.

It is thought that the invention in many of its attendant advantages will be understood from the foregoing without further description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts and in the apparatus of which they form a part without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim: I

1. In a feeding mechanism for die presses and the like, the combination of a stack holder, sheet-holding means for sheets taken from said holder, air suction means for removing sheets from the holder to said sheet holding means, a controlling element engageable by a sheet in said sheet holding means, a feeding slide for propelling sheets successively out of said sheet holding means to be operated on by said press, and means whereby said controlling element controls the operation of the slide and also the partial vacuum of said suction means.

2. In a feeding mechanism for die presses and the like, the combination of a stack holder, sheet-holding'means for sheets taken from said holder, having a slot adapted to hold a plurality of sheets and extending downward below said holder, air suction means for removing sheets from the holder to a point over said slot into which slot said sheets are dropped by gravity upon 3. In a feeding mechanism for die presses and the like, the combination of a stack holder, sheet-holding means for sheets taken from said holder, having a slot adapted to hold a plurality of sheets and extending downward below said holder, suction means for removing sheets from the holder toa point over said slot into which slo-t said sheets are dropped by gravity upon release from said removing means, a. transverse pin extending into said slot, and engageable by a sheet therein, a feeding slide for propelling sheets successively out of said slot to be'op-erated on by said press, and means whereby said pin controls the partial vacuum of said suction means.

4. In a feeding mechanism for die presses and the like, the combination of a feed way, a stack holder arranged adjacent said feed way, suction devices for removing blanks singly from a. stack in said holder'and arranging them in registration with said feed way, and means controlling the partialvacuum action of said suction devices when more than a single blank has been arranged in registration with said feed way.'

5. In a feeding mechanism for die presses and the like, the combination of a feed way, a stack holder arranged adjacent said feed way, suction devices for removing blanks singly from a stack in said holder and arranging them in registration with said feed way, and means controlling the partial vacuum of said suction devices to break the suction when more than a single blank has been arranged in registration with said feed way.

6. In a feeding mechanism for die presses and the like, the combination of a feed way, air suction means inserting blanks singly in said feed way, and means for preventing the formation of the partial vacuum of said inserting means, when more than a single blank has been inserted in said feed way.

7. In a feeding mechanism for die presses and the like. the combination of a feed way, air suction meansfeeding blanks to said feed way, and means for preventing the formation of the partial vacuum of said feeding means, when more than a predetermined number of blanks have been fed into said feed way at a single feeding.

8. In a feeding mechanism for die presses and the like, the combination of a feed way, air suction means for feeding blanks into said feed way, and means arrangeable in the path of travel, during the operative stroke of said feeding means to prevent the formaxtion of the partial vacuum of said feeding-means, when more than a predetermined number of blanks have been fed into said feed way at a single feeding.

9. In a feeding mechanism for die presses and the like, the combination of a feed way, a stack of blanks arranged adjacent said feed way, meansfor inserting blanks from. said stackinto said feed way, a latch arm for rendering said means inoperative, and normally opened through theagency of a blank being fed into said feed. way, and means more than a single blank has been positioned in said feed way.

10. In a feeding mechanism for die presses and the like, the combination of individual sheet-feeding means, means for delivering sheets successively to said sheetfeeding means, and devices for stopping the operation of said sheet-feeding means and also for separately stopping the operation of said delivering means, said stopping devices being actuated by an extra sheet when delivered by said deliverin means.

FRE CREDITY 

